Properties and Distribution of Intracellular Putrescine in a Pseudomonas

Abstract

Kim, Ki-Han (Wayne State University, Detroit, Mich.). Properties and distribution of intracellular putrescine in a Pseudomonas . J. Bacteriol. 91: 193–197. 1966.—A Pseudomonas species which contains putrescine as the only intracellular polyamine was used to study the distribution of putrescine in the cells and the changes in putrescine content upon nitrogen or carbon and nitrogen starvation. In the cell-free extract, approximately 80 to 90% of the putrescine was found in the soluble fraction, and the rest was found in the ribosomal fraction; 50% of the putrescine could be removed from the cells by nitrogen starvation. Putrescine content in the ribosomes prepared from nitrogen-starved cells was about one-half of that in the unstarved cells. Putrescine was found in both 30 S and 50 S ribosomal particles. In the presence of 10 −3 m Mg ++ , the ribosomal particles did not exchange bound putrescine for free putrescine, but did incorporate free spermine from the medium. Cells grown on glucose-NH 3 medium contained large amounts of acetyl putrescine. Cells grown on putrescine contained negligible amounts of acetyl putrescine, but readily formed acetyl putrescine when subjected to starvation.